In related arts, as a starter which is used to start an engine of an automobile, a configuration which includes a motor configured to generate a rotating force, an output shaft configured to rotate by receiving the rotating force, a pinion mechanism provided on the output shaft slidably in an axial direction, the pinion mechanism including a pinion capable of meshing with a ring gear of the engine, and an electromagnetic equipment which biases a pressing force on the pinion mechanism toward the ring gear, has been known.
The electromagnetic equipment includes an exciting coil which forms magnetic path by being excited, and a plunger configured to move by being suctioned by the exciting coil. The pinion mechanism includes a pinion inner capable of sliding along the output shaft by receiving the pressing force from the electromagnetic equipment. The pinion is fitted with the pinion inner by a helical spline fitting, and the pinion is movable provided in the axial direction with respect to the pinion inner (e.g. see patent literature 1).
Under the configuration, when the electromagnetic equipment is energized, the plunger moves and the pressing force is biased on the pinion mechanism. Then, the pinion is pushed out toward the ring gear while rotating around the axis along the helical gear provided on the drive shaft.
At this time, the pressing force and a rotating force is acting on the pinion. For this reason, although a meshing phase between the ring gear and the pinion is misaligned and end faces of the ring gear and the pinion contacts, the pinion is capable of being meshed with the ring gear smoothly afterward.
When the pinion meshes with the ring gear and is linked, the rotation force of the motor is transferred to the ring gear via the output shaft and the pinion, and then the engine starts by the ring gear to rotate.
As the engine starts, and when a rotating speed of the ring gear becomes higher than that of the pinion, a one way clutch function of a clutch mechanism provided on the starter functions to run idle the pinion, and it is configured that the rotation of the ring gear is not transferred to the motor of the starter.
Furthermore, in recent years, in order to improve fuel consumption of an automobile and/or to reduce exhaust gas, an automobile is provided in which an idling stop function is equipped, wherein the idling stop function causes an engine in an idling state to temporary stop upon when the automobile stops, for example, to wait for a traffic light, and the idling stop function restart the engine when the automobile starts moving again. Since the starter described in the patent literature 1 is capable of meshing the pinion with the ring gear smoothly, the starter can be adopted to automobiles which are equipped with the idling stop function described above.